package com.heima.kafka;

import org.apache.kafka.clients.consumer.*;
import org.apache.kafka.common.TopicPartition;

import java.time.Duration;
import java.util.Collections;
import java.util.Map;
import java.util.Properties;

/**
 * kafka 消费者
 */
public class ConsumerQuickStart {
    public static void main(String[] args) {
        // 1.添加kafka的配置信息
        Properties prop = getStringKafkaConsumer();
        try (
                // 2.创建消费者对象
                KafkaConsumer<String, String> consumer = new KafkaConsumer<>(prop)
        ) {

            //3.订阅主题
            consumer.subscribe(Collections.singletonList("topic--"));

            //当前线程一直处于监听状态
            try {
                while (true) {
                    //4.获取消息
                    ConsumerRecords<String, String> consumerRecords = consumer.poll(Duration.ofMillis(1000));
                    for (ConsumerRecord<String, String> consumerRecord : consumerRecords) {
                        System.out.println(consumerRecord.key());
                        System.out.println(consumerRecord.value());
                        // 使用手动提交需要配置 enable.auto.commit=false
                        // consumer.commitSync(); // 同步提交当前最新的 offset
                        // consumer.commitAsync(); // 异步提交当前最新的 offset

                        // 同步 + 异步: 异步提交失败后, 使用同步提交
                        consumer.commitAsync();
                    }
                }
            } catch (Exception e) {
                System.out.println("异步提交异常：" + e.getMessage());
            } finally {
                try {
                    consumer.commitSync();
                } finally {
                    consumer.close();
                }
            }
        }

    }

    private static Properties getStringKafkaConsumer() {
        Properties properties = new Properties();
        //kafka的连接地址
        properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.200.130:9092");
        //消费者组
        properties.put(ConsumerConfig.GROUP_ID_CONFIG, "group2");
        //消息的反序列化器
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
                "org.apache.kafka.common.serialization.StringDeserializer");
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
                "org.apache.kafka.common.serialization.StringDeserializer");
        // 关闭自动提交
        properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false");
        return properties;
    }
}
